ZEB2 and ZEB1 expression in a spontaneous canine model of invasive micropapillary carcinoma of the mammary gland.

ZEB1 and ZEB2 have been recently related to cancer prognosis. We investigated their expression and its association with clinicopathological parameters and overall survival in invasive micropapillary carcinoma (IMPC), which is a metastasising neoplasm of the canine mammary gland. Immunohistochemical evaluation showed nuclear and cytoplasmic staining for ZEB2 and nuclear staining for ZEB1. 'In situ' areas presented higher positivity for cytoplasmic ZEB2 than invasive areas of IMPC did (p = 0.03). ZEB1 positivity was associated with a low histological grade (p = 0.01). A shorter overall survival rate was observed in IMPCs that were positive for cytoplasmic ZEB2 (p = 0.04). Antibodies specificity in canine species was confirmed by western blot. Our results indicated that cytoplasmic ZEB2 appears to be an important factor in the early stages of malignancy and predicts a poor overall survival rate for IMPC in this canine mammary cancer model. ZEB1 downregulation appears to be associated with the dedifferentiation process of IMPC.